Name common contraindications to lumbar puncture.

• A. Suspected increased ICP, papilledema, focal neurologic deficit with mass lesion, coagulopathy or anticoagulation.
• B. Normal ICP without mass lesions and normal coagulation.
• C. History of allergy to penicillin.
• D. Age under 6 months.

Answer: (A)

The main idea is that a lumbar puncture can worsen brain injury if there are conditions that raise intracranial pressure or increase bleeding risk. Suspected increased intracranial pressure is a red flag because removing CSF can create a pressure gradient that pushes brain tissue downward, risking herniation. Papilledema is a sign of raised ICP, so performing an LP under those circumstances could trigger dangerous brain shift. A focal neurologic deficit with a mass lesion points to a space-occupying process; again, removing CSF could exacerbate pressure dynamics and herniation. Coagulopathy or anticoagulation increases the chance of a spinal or subarachnoid hematoma during needle insertion, which can injure neural structures.

In contrast, normal ICP without mass lesions and normal coagulation do not impose these risks, so they are not contraindications. A history of allergy to penicillin doesn’t relate to the procedure, and age under 6 months is not an absolute contraindication—lumbar puncture can be performed in infants with appropriate technique and precautions.